ambridge ceramics: Tips for getting the best from all ceramic restorations.

Getting the best from All Ceramic restorations

We love to share tips with our clients to help us work together to produce the best results we can for our patients.

This month we are going to share an important consideration when restoring with All Ceramic restorations, in particular we will be looking at the effects underlying stump shades have on the Value of all ceramic restorations.

Firstly, using an All Ceramic material offers the possibility of truly outstanding aesthetic results due to the lack of metal or reflective substructures, yet still offering very high strength. One of the reasons the results are superior is in the case of metal bonded (PFM) the frameworks are non-light transmittal, an aesthetic problem right from the start, plus as they are almost black in colour, and can be quite difficult to mask (which can often be the case with non translucent or ‘white’ Zirconia).

The main disadvantage of the Zirconia framework is the higher rate of chipping that can occur with the final layered ceramic. This can be due to many factors such as the critical material handling or if the frameworks have not been designed to support the layering porcelain in a very particular way.

So, with e.max press we have excellent strength when bonded as shown in this independent study.

These also offer superb choices of the pressed ceramic material to base the restoration which will provide a beautiful result.

Due to the translucency, one of the biggest factors involved in obtaining a successful result however is receiving adequate information regarding the shade of the preparation we are restoring upon.

As this is not normally a big factor with traditional restorations (due to the fact the substructure of alloy or zirconia will normally mask this) and it can easily be overlooked, the results of which will badly effect the Value of the crown and make it look dull and dead.

Here we look at the importance of communicating this information, and particularly how providing good photographs.

What do we need to use?

Digital Camera

It doesn't really matter what you're preferred brand is but a decent DSLR camera is essential for relaying accurate and genuinely useful detailed images to the lab.

We do get images from mobile devices and although some information is better than none at all, it really doesn't give us the depth of information needed to include the fine detailing that can really make a crown come to life and blend in naturally with the surrounding teeth.

Ivoclar Vivadent Natural Die (ND) shade guide

Ivoclar Vivadent shaded resins to match the ND shade guide.

Ivoclar Vivadent have created a range of ND shade guides for relaying the colour of the underlying preparation to the laboratory which can then use some special resins to pour the preps in the correct shade. This allows them to confirm that the different All Ceramic crowns or veneers match up even as they are building them and finishing at the laboratory.

At our laboratory we have taken this one step further by individually matching cement die spacers to each individual ND shade tab, this allows us to use the accurate model materials and systems we know get accurate results whilst also ensuring we have dealt with any shade correction issues properly.

And because we have different stones used for different indications we also matched each individual paint to give the same final shade regardless of which colour stone it is painted onto

Sounds like a lot of effort, how much of a difference does it really make?

If you look at the model we have painted to simulate the ND shades below you can see the variations on the 15,14 & 13, with 15 & 14 being quite similar and the 13 being obviously more discoloured (a situation that occurs quite frequently on the cases we restore)

We pressed 3 simple blank veneers in e.max All Ceramic, each of an even thickness, and as you can see were all the same shade.

As you can see, these blanks aren't even that translucent so we have a potential issue even on LT pellets if the underlying shade is not taken into account.

As these are placed upon the different underlying stump shades you can see how it changes the veneer shade considerably.

This is more pronounced on the 13 but even shows on the 15 & 14 which had very little underlying shade variation

So we can see how making these veneers without the information regarding the shade of the stumps we were restoring on this would have been a disaster!

Although it is possible to use a range of coloured cements that Ivoclar provide to correct this, we believe it is always better to have the correct information to begin with and provide restorations to the surgeon which have already compensated for the underlying stump shade to keep your inconvenience to a minimum.

Case by Dr Gurs Sehmi

We are very fortunate to work with surgical partners who already provided us with this type of essential information even before we had the ND shade guides to assist us.

So in addition to providing us a clear photo with the desired shade tab included

In addition Dr Sehmi provided a shade of the underlying stump shades, which was very important in this case as it had a veneer and crown on 2 centrals, with a marked difference in the underlying tooth shade.

Dr. Sehmi used the shade guides he had available (the ND shade guides are not very well known, which in part is what prompted us to write this article) to relate the stump shades to us at the lab which we then used to paint the preps the correct colour, then by referring to a shade matching chart (available on page 58 & 59 of this pdf) we selected the appropriate e.max pellet to even up the e.max cores our ceramists would work on.

As all our ceramic team work with an iPad at their side which streams all the images you provide us with to them via a central media storage system. They always use these images and any others you send us, and any other information provided during the build of your restorations to ensure that all the vital characterisation is included.

We love getting these images to help us get the right results for you and your patients, so the more the better!

By using all this information we managed to produce veneers which matched the smile even though we were compensating for different completely different shades underneath.

The patient was delighted with their new smile and we really appreciate it when you take the time to provide us with some of these crucial extra photographs that help us give your patients a great result.

By providing good photographs and including the stump shades it ensures both the laboratory and surgery are working from the same reference points.

Using this, even with really tricky underlying shades it is possible to get fantastic, natural looking e.max all ceramic restorations.

But without this vital information even the slightest difference can throw the final shade value off by enough to make the restoration stand out and look out of place.

By improving the communication and working to good photographs we can provide veneers like the ones you see below, which were used for BACD accreditation

Can you spot them?